in a Porous Metal-Organic Framework [Zn 2 (BPnDC) 2 (bpy)]

Transcription

1 Supporting Information Stepwise and Hysteretic Sorption N 2, O 2, CO 2, and H 2 Gases in a Porous Metal-Organic Framework [Zn 2 (BPnDC) 2 (bpy)] Hye Jeong Park and Myunghyun Paik Suh Contribution from the Department of Chemistry, Seoul National University, Seoul , Republic of Korea mpsuh@snu.ac.kr 1

2 General Methods. All chemicals and solvents used in the syntheses were of reagents grade and used without further purification, except that purchased anhydrous methanol was further dehydrated by using the activated molecular sieves prior to use. Infrared spectra were recorded with a Perkin-Elmer Spectrum One FT-IR spectrophotometer. Elemental analyses were performed with a Perkin-Elmer 2400 Series II CHN analyzer. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were performed under N 2 at a scan rate of 5 o C/min, using TGA Q50 and DSC Q10 of TA instruments, respectively. High-resolution powder X-ray diffraction (PXRD) was measured with a synchrotron radiation source (λ = Å, scan speed = 0.01 o /sec, step size = 0.01 o in 2θ) at Beamline 11A1 RXS, Pohang Accelerator Laboratory (PAL), Pohang, Korea. The temperature dependent PXRD data were recorded on a Bruker Small-Angle X-Ray Scattering (SAXS) with General Area Detector Diffraction System (GADDS) at National Instrumentation Center for Environmental Management (40 kv and 45 ma for Cu Kα (λ = Å), exposure time = 180 sec, step size = 0.02 o in 2θ). {[Zn 2 (BPnDC) 2 (bpy)] 2DEF 2MeOH} n (1). H 2 BPnDC (0.054 g, 2.0 x 10-4 mol) and bpy (0.016 g, 1.1 x 10-4 mol) were dissolved in DEF (6 ml), and Zn(NO 3 ) 2 6H 2 O (0.080 g, 2.7 x 10-4 mol) was dissolved in MeOH (3 ml). The solutions were mixed in a glass bottle, which was then tightly capped with silicone stopper and aluminum seal, and then heated at 80 ºC for 24 h. On cooling to room temperature, colorless rod-shaped crystals formed, which were filtered, and washed briefly with MeOH. Yield: g (67%). FT-IR for 1 (Nujol mull): ν O-H, 3608, 3468; ν C=O(DEF), 1670; ν C=O(BPnDC), 1658; ν C=C(aromatic), 1607; ν O-C=O(carboxylate), 1558 cm -1. Anal. Calcd for Zn 2 C 52 H 54 O 14 N 4 : C, 57.31; H, 4.99; N, Found: C, 56.63; H, 4.52; N, {[Zn 2 (BPnDC) 2 (bpy)] 6MeOH} n (1m). Crystals of 1 were immersed in anhydrous MeOH for 12 h, and the solvent was decanted. Fresh anhydrous MeOH was replenished and the crystals were immersed for another 12 h to exchange all DEF guest molecules with MeOH. FT-IR for 1m (Nujol mull): ν O-H, 2

3 3369; ν C=O(BPnDC), 1659; ν C=C(aromatic), 1607; ν O-C=O(carboxylate), 1557 cm -1. Anal. Calcd for Zn 2 C 46 H 48 O 16 N 2 : C, 54.40; H, 4.76; N, Found: C, 53.90; H, 4.58; N, [Zn 2 (BPnDC) 2 (bpy)] n (SNU-9). 1m was heated in a Schlenk tube at 60 o C under vacuum for 1.5 h. FT-IR (Nujol mull): ν C=O(BPnDC), 1667; ν C=C(aromatic), 1609; ν O-C=O(carboxylate), 1588 cm -1. Anal. Calcd for Zn 2 C 40 H 24 O 10 N 2 : C, 58.35; H, 2.94; N, Found: C, 57.70; H, 2.71; N, Low-Pressure Gas Sorption Measurements. The gas adsorption-desorption experiments were performed using an automated micropore gas analyzer Autosorb-1 or Autosorb-3B (Quantachrome Instruments). All gases used were of % purity. Sample was predesolvated by heating 1m in a Schlenk tube at 60 C under vacuum for 2 h, and the measured amount of the dried solid was introduced to the gas sorption apparatus and then activated at 60 o C under vacuum for 1 h. The N 2 and O 2 gas sorption isotherms were monitored at 77 K and 87 K, and the H 2 gas isotherm was measured at 77 K. The CO 2 and CH 4 gas sorption isotherms were measured at 195 K and 273 K at each equilibrium pressure by the static volumetric method. After each gas sorption measurement, sample weight was measured again precisely. Surface area and total pore volume were determined from the N 2 gas adsorption isotherm at 77 K. For estimation of multipoint BET (Brunauer-Emmett-Teller) and Langmuir surface area from the N 2 adsorption data, the data were taken in the range P = atm and P = atm, respectively. High-Pressure Gas Sorption Measurements. High pressure gas sorption isotherms were measured by the gravimetric method using a Rubotherm MSB (magnetic suspension balance) apparatus. All gases used were of % purity. The H 2 sorption isotherms were measured at 77 K. The CO 2 and CH 4 sorption isotherms were measured at 298 K. Sample was prepared by heating 1m in a Schlenk tube at 60 C under vacuum for 2 h, and the measured amount of the dried solid was introduced into the gas sorption apparatus and then activated at 60 o C under vacuum for 12 h. Prior to gas sorption measurement, the He isotherm (up to 90 bar) was measured at 298 K to obtain volume of the framework skeleton. The excess sorption isotherms were measured and the data were corrected for buoyancy by 3

4 multiplying the volume of the framework skeleton by the density of corresponding gas at each pressure and temperature. [S1] The total amount of H 2 adsorption was estimated by using the densities of the framework skeleton and the crystal. [S2] In the conversion of gravimetric data (wt%) to volumetric ones (gl -1 ), the crystallographic density of desolvated sample of 1m (d = g/cm 3 ) was applied. X-ray Crystallography. Diffraction data of 1 and 1m were collected at 100 K on a ADSC Quantum 210 CCD diffractometer with synchrotron radiation (λ = for 1 and for 1m) at Macromolecular Crystallography II 6C1, Pohang Accelerator Laboratory (PAL), Pohang, Korea. The crystals were coated with Paraton oil to prevent the loss of guest molecules. The diffraction data were collected using a phi scan method through a total of 360 o rotation. The raw data were processed and scaled using the program HKL2000. The crystal structure was solved by direct methods [S3] and refined by full-matrix least-squares refinement using the SHELXL-97 computer program. [S4] The positions of all non-h atoms were refined with anisotropic displacement factors. The H atoms were positioned geometrically using a riding model. The densities of the disordered guest molecules in 1 and 1m were flattened by using the SQUEEZE option of PLATON. [S5] CCDC (1) and (1m) contain the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via References: [S1] NIST chemistry webbook (thermophysical properties of fluid systems); [S2] M. Dinca, A. Dailly, Y. Liu, C. M. Brown, D. A. Neumann, J. R. Long, J. Am. Chem. Soc. 2006, 128, [S3] Sheldrick, G. M. Acta Crystallogr. 2008, A64, [S4] Sheldrick, G. M. SHELEX97, Program for the crystal structure refinement; University of Göttingen: Göttingen, Germany, [S5] Spek, A. L. PLATON A Multipurpose Crystallographic Tool; Utrecht University, Utrecht, The Netherlands,

5 Figure S1. An ORTEP drawing of 1, showing the coordination environment of two independent Zn II ions. Thermal ellipsoids are drawn with 30% probability. Symmetry transformation: a, x+1/2, y+1/2, z; b, x, -y, z-1/2; c, x+1/2, y-1/2, z. 5

6 Supplementary Material (ESI) for Chemical Communications Figure S2. X-ray structure of 1. (a) View seen on the ab plane, showing the 2D layers are repeated in the staggered manner with the ABABAB sequence. (b) Doubly interpenetrated 3D structure seen on the ab plane, (c) on the ac plane, and (d) on the bc plane. Blue and yellow colors represent each framework of the doubly interpenetrated structure. (e) A view showing the 3D curved channels. The accessible surface in the channels is represented by green color. 6

7 Figure S3. TGA/DSC trace for 1. 7

8 Figure S4. The temperature dependent PXRD patterns of 1 (from R.T. to 330 o C ). 8

9 Figure S5. An ORTEP drawing of the asymmetric unit of 1m. Thermal ellipsoids are drawn with 30% probability. 9

10 Figure S6. Comparison of the crystallographic asymmetric units of 1 (red) and 1m (blue) by superimposition. 10

11 Figure S7. The synchrotron (λ = Å) PXRD patterns measured at room temperature of (a) 1 assynthesized, (b) the simulated from single-crystal X-ray data of 1, (c) guest-exchanged solid with MeOH (1m), (d) the simulated from single-crystal X-ray data of 1m, (e) SNU-9 prepared by drying 1m at 60 o C under vacuum for 1.5 h, and (f) a solid resulting after exposure of the sample of (e) to MeOH vapor for 6 h. 11

12 Figure S8. TGA traces for 1, 1m, and SNU-9. 12

13 Figure S9. The temperature dependent PXRD patterns of 1m (from R.T. to 350 o C ). 13

14 Figure S10. Langmuir fits for two-step CO 2 adsorption isotherms. (a) At 195 K measured up to 1 atm. The blue dashed lines is the fit of the first step adsorption (P < 0.15 atm) and the red dashed line is the fit for the second step adsorption (P > 0.4 atm). (b) At 298 K measured under high pressures. Langmuir fits for the first step (0 6 bar) and the second step (14 50 bar) adsorptions are indicated by blue and red dashed lines, respectively. 14

15 Table S1. Crystallographic Data for 1 and 1m [Squeezed Data] 1 1m formula Zn 2 C 40 H 24 N 2 O 10 Zn 2 C 40 H 24 N 2 O 10 crystal system monoclinic monoclinic space group C2/c C2/c fw a, Å (4) (4) b, Å (4) (4) c, Å (5) (5) β, deg (3) (3) V, Å (3) 9894(3) Z 8 8 ρ calcd, g/cm temp, K λ, Å μ, mm GOF (F 2 ) F(000) reflections collected independent reflections 7644 [R(int) = ] 6139 [R(int) = ] independent reflections [I > 2σ(I)] completeness to θ max, % data refined/parameters/restraints 7644 / 487 / / 487 / 0 θ range for data collection, deg diffraction limits (h, k, l) -25 h 24, -22 h 22, -20 k 20, -19 k 19, -30 l l 27 refinement method Full-matrix least-squares on F 2 Full-matrix least-squares on F 2 R 1, wr 2 [I > 2σ(I)] , a b , a c R 1, wr 2 (all data) , a b , a c largest peak, hole, eå , , a R = Σ F o - F c /Σ F o. b wr(f 2 ) = [Σw(F o 2 - Fc 2 ) 2 /Σw(F o 2 ) 2 ] ½ where w = 1/[σ 2 (F o 2 ) + (0.1361P) 2 + (4.5286)P], P =(F o 2 + 2Fc 2 )/3 for 1. c wr(f 2 ) = [Σw(F o 2 - Fc 2 ) 2 /Σw(F o 2 ) 2 ] ½ where w = 1/[σ 2 (F o 2 ) + (0.0955P) 2 + (28.14)P], P =(F o 2 + 2F c 2 )/3 for 1m. 15

16 Table S2. Gas adsorption data of SNU-9 for N 2, O 2, H 2, CO 2, and CH 4 gases gas T (K) P (bar) surface area pore volume (m 2 g -1 ) a,b (cm 3 g -1 ) mmol of gas/ g of host wt% gas Gas adsorbed/ volume of host c (gl -1 ) N a, 820 b O H d, 6.23 e 40.2 d, 68.9 e CO CO CO CH CH a Langmuir surface area. b BET surface area. c The values are calculated by mass of adsorbed gas/g x density of sample (density: 1106 gl -1 ), assuming that the cell volumes of 1m is retained in its desolvated solid (SNU-9). d Excess adsorption capacity. e Total adsorption capacity at 77 K and 90 bar, which is estimated by using the densities of the framework skeleton and the crystal. 16

17 Table S3. Adsorption and Desorption Data for N 2 Uptake in SNU-9. N 2 at 77 K N 2 at 87 K P / atm V ads / cc g -1 P / atm V ads / cc g -1 P / atm V ads / cc g -1 P / atm V ads / cc g E E E E E E E E E E E E E E E E E E E

18 Table S4. Adsorption and Desorption Data for O 2 Uptake in SNU-9. O 2 at 77 K O 2 at 87 K P / atm V ads / cc g -1 P / atm V ads / cc g -1 P / atm V ads / cc g -1 P / atm V ads / cc g E E E E E E E E E E E E E E E E

19 Table S5. Adsorption and Desorption Data for CO 2 and CH 4 Uptake in SNU-9 at 195 K. CO 2 at 195 K CH 4 at 195 K P / atm V ads / cc g -1 P / atm V ads / cc g -1 P / atm V ads / cc g -1 P / atm V ads / cc g E E E E E E E

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21 Table S6. High Pressure CO 2 and CH 4 Uptake in SNU-9 at 298 K. CO 2 at 298 K CH 4 at 298 K P / bar Excess wt% P / bar Excess wt% P / bar Excess wt% P / bar Excess wt%

22 Table S7. High Pressure H 2 Uptake in SNU-9 at 77 K. P / bar Excess adsorbed / wt% P / bar Excess adsorbed / wt%

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